Cutting tool grinder



Feb. 7, 1956 P. M. NEwsoM CUTTING TOOL GRINDER Filed Sept. 18, 1952 fri/enfer Pau/ M Nen/Jam United Sees 2,133,553 VcUrrrNG rrooL GRINDER Paul M. Newsom, Allison, Tex. Application September- Y18,1952, Serial N0. 310,252 Y 1 claim. (ci. 51 11V1) i This; invention relatesto the sharpening of cutting implements-.such as knives and theelike and is directed particularly 1to anA improved `rotary grinding device.

`A principal object of the presentinvention is to provide av rotary grindingdevice `designed particularly for the sharpening of knives and the like, wherein a pair of coacting grinding disks are provided and yieldably maintained in abutting coaxial relation whereby a uniform grinding of the edge of a knife on both faces of the blade is obtained when such edge is inserted between the grinding disks.

Another object of the invention is to provide a grinding device of the character stated which is adapted to be coupled to the shaft of a motor or may be supported for rotation by hand, wherein a pair of axial grinding disks having bevelled coacting edge faces are supported for unitary rotation and yieldably pressed together so that when a knife edge is placed between the bevelled edges of the disks such edge will be ground uniformly on both sides and the blade will be protected against overgrinding or damage in the event that it is pressed with more than the required force between the disks, by the separatory movement of the latter against said yieldv able means.

Other objects and advantages of the invention will become apparent as the description of the saine proceeds and the invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawing forming a part of the specification, with the understanding, however, that the invention is not to be limited to the exact details of construction shown and described since obvious modifications will occur to a person skilled in the art.

In the drawing:

Figure 1 is a view partly in elevation and partly in vlongitudinal section of a grinding device constructed in accordance with the present invention, showing the same connected with the armature shaft of an electric motor.

Figure 2 is a transverse section taken substantially on the line 2-2 of Figure 1.

Figure 3 is a sectional view taken substantially on the line 3-3 of Figure l.

Figure 4 is a view in side elevation of one of the disk supporting sleeves.

Figure 5 is a view in a lock ring, in side elevation.

Referring now more particularly to the drawing there is shown mounted upon a suitable base 10, an electric motor which is generally designated 12 and which has the armature shaft 14, and a post 16 having a bearing opening 18 therein which is coaxial with the armature shaft 14.

Inrthe bearing opening is a bearing unit 20 which may be of the roller type or merely a bronze bushing.

In accordance with the present invention there is provided the shaft 22 which is provided with the longitudinal splines 24, for the purpose hereinafter set forth.

The outer ends of the shaft 22 are continued by the axial trunnion extensions 26. One of these trunnions 26 is secured to the end of the motor shaft 14 by a suitable means 28, as shown, while the other trunnion 26 is `st ipported in the bearing 20` of thepost 16.

Enclosing the shaft 22 are sleeves 30 which are provided with the spline grooves 31 in which engage the splines 24 of the encircled shaft.

At the outer end of each sleeve 30 is a washer 32 which encircles the shaft trunnion 26 and also encircling veach shaft trunnion` 26 and in spaced relation with the washer 32 is a second washer. 33.

Interposed between each pair of washers 32 and 33 is an expansionspring'34. j

As shown in Figure 1 the outer washer 33 adjacent to the post 16 bears against'the post and the spring 34 exerts its force against this'washer to press inwardly against the adjacent washer 32 while upon the opposite trunnion 26 the outer washer 33 is held in place by a key 35 so that the adjacent spring 34 presses inwardly against the adjacent washer 32. Accordingly it will be seen that the two springs 34 are constantly pushing inwardly against the adjacent ends of the sleeve 30.

As illustrated the sleeves 30 are in end opposed relation and adjacent to its inner end, each sleeve has formed therearound the screw threads 36 for the purpose about to be described.

Encircling the two sleeves 30, and positioned between the threads 36, are two grinding disks 37 each of which is supported upon a sleeve and each of which has the corner thereof adjacent to the other'dsk bevelled as indicated at 33 so that the two bevelled corners, or portions, of the disks form an annular V slot in which the edge of a knife or other cutting implement is inserted for grinding. Y

Each of the disks has formed in the face thereof which opposes the other disk, the circular recess 39. In each of these recesses there is positioned, in encircling relation with the adjacent sleeve 30, a metal washer 40 and a liber washer 40a, between the washer 40V and the bottom of the recess.

As shown the washers 40 are in opposed contacting relation and are secured in place, on the sleeve by the lock, or snap rings 41.

Encircling each of the sleeves 30 at the outer side of grinding disk 37 carried thereon, is a securing nut 42 which is in engagement with the threads 36 of the supporting sleeve and interposed between the nut andv the grinder disk is a fiber washer 42a. These nuts 42 when threaded against the adjacent disk, force the disks together, as will be readily apparent.

ln the use of the present grinding device, the motor 12 whenv operated will, of course, rotate the two disks 37 and the edge of the blade to be sharpened is inserted in the V slot 33', formed by the beveled edges 33 of the disks. This V slot will give the proper taper to the edge as it is ground and it will be seen that if too great a pressure is applied tothe knife so as to force the edge in between the disks, the sleeves 30 will Vshiftapart or outwardly against the tension of the springs 34 so that the blade will not be ground down to too great an extent.

It will be seen from the foregoing that there is provided by the present invention a relatively simple device by means of which a knife or other suitable tool can be easily and quickly sharpened on one or both sides of its cutting edge.

I claim:

In a tool grinding device, a flat, elongated base, a post rising from one end of the said base, a shaft having one end journaled in said post, an electric motor having a rotor shaft mounted on the other end of said base, a coupling between the other end of the first shaft and said rotor shaft, said motor providing the sole support for said other end of said rst shaft, the lirst shaft bep atented Feb. 7, 1956V ills termed with a plurality l lensitudinal splines tenedate its ends, a pair of sleeves on said shaft and having their inner surfaces formed with spline grooves @agegsdwitll Ssifl splines, a pair of grinding disks on tlieiimer ends Q f said Sleeves and having their. adiaem peripheral edges oppositely beveled to form a circumferential groove olfVV-shaped cross` section, means Yfor Sllrping said disks for rotation with said sleeves and the shaft comprising annular grooves in said sleeves adjacent the inner Vend thereof, lock rings received in said grooves, metallic Washers received on said sleeves and engaging Said llock rings, liber Washers received on said l sleeves and engaged on saidjmetallic Washers, circular recesses in the opposed surfaces ofsaid disks receiving said washers with said fiber washers engaging the opposed faces of said recesses and nut threadedly received on said sleeves engaging the outer radial faces of said disks to holdV said. disks inA engagement with said ber washers andfprevent rotation of s aid disks relative to said sleeves, Vand spring-tensioned means comprising a washer on saidshaft engaging the outer end of each sleeve, a compression spring on said shaft engaging said last 'a'raaus i l l f vf" named washer, a second washer on said shaft engaging said 'spring'd the iii'rei surface of said p's'tf''secvond compression spring engaging the other washer and a further Washer engaging said second spring and a pin extend` ing through said shaft, whereby said sleeve are urged toward each other to hold the inner opposed surfaces of said disks in yielding ahuttingrelationship.

References Gite-i is the; fils, af; this; Patent UNl-'reD STATES. PATENTS 288,099 Myels :1T-.- --l'w-T--r'r-s NQV' ,6v 1883 466,293 'V l 'l 1891 726,974 1903 945,499 1910 1,068,973 Brown July 29, 1913 V1,415,375 Luebben May 9, 1922 1,558,194 1925 1,955,129l 1934 2,114,106 5 1,938 A420314 1947 2,570,564 i 1951 2,546,653 i' 1953 

